Edge Angle as Cycles Shader input
This solution doesn't give you a perfect angle based control but it is sort of a better version of the pointiness value map.

You will have to download a daily 2.79 build from https://builder.blender.org/download/ to get access to the bevel node.



The viewer node is just an emission shader to view the value map.



You can tweak this map even further with a colorramp node of course.